1. Technical Field
The present invention relates to a turbine or compressor device comprising (including, but not limited to) a rotor having a first rotor section with at least one disc-shaped or annular element. The annular element has a multiplicity of blades arranged in series on a circumferential path for guiding a gas flow, together with a second, elongate rotor section, that projects at right-angles from the rotor disc and which includes a rotor shaft connected to the rotor disc. A first and second bearing are fitted at a distance from one another along the rotor shaft, and the first bearing is arranged closer to the rotor disc than the second bearing. The invention further relates to a method for assembling such a device.
The term turbine device is intended to mean a machine in which the energy present in a flowing fluid (gas, vapor or liquid) is converted into rotational energy by means of blades or vanes. The term compressor device is intended to mean a machine having an inverse function; that is to say, rotational energy is converted by means of blades or vanes into kinetic energy in a fluid. The device comprises a rotor and a stator interacting therewith.
In the following, the device comprises a turbine device, which in turn forms part of a gas turbine. This is a preferred, but in no way restrictive application of the invention. The term gas turbine is intended to mean a unit that at least comprises a turbine wheel and a compressor wheel driven by the former, together with a combustion chamber. Gas turbines are used, for example, as engines for vehicles and aircraft, as prime movers for vessels, and in power stations for generating electricity.
The rotor may take the form both of a radial rotor and an axial rotor. Furthermore, the term elongate rotor section is intended in the context of the present disclosure to mean the rotor shaft and additional components intended to rotate on the rotor shaft, such as bearings and spacers between the bearings and gears.
2. Background Art
When assembling a turbine device comprising the rotor and the stator, the rotor must be balanced. According to the state of the art, the rotor bearings are fitted in their respective bearing positions from different ends of the rotor shaft and the first rotor section has the bladed disc-shaped or annular element which is detachably connected to the rotor shaft by means of a bolted joint, for example. This is done once the bearing that is to be arranged closest to the disc-shaped or annular element has been arranged in the intended position. The balancing is usually performed in a number of stages in which further components, such as spacers between the bearings, gears and other components intended to rotate therewith are successively arranged on the rotor shaft. During balancing, the rotor is rotated by means of a belt or compressed air, for example, and material is removed from, or added to the rotor in order to improve its balance.
Once the rotor has been balanced, it is at least partially dismantled in order to be able to arrange the stator parts at their intended positions around the rotor shaft. In this process of dismantling, the disc-shaped or annular elements, and possibly the bearings, are detached from the rotor shaft. Once the stator parts have been arranged at their intended positions, the rotor is reassembled. This makes it impossible to check how well the rotor is balanced in its final assembled state.
It has been learned (emerged) that despite the balancing that is carried out as described above, a significant proportion of the rotors manufactured in this way still have a certain undesirable imbalance.